National 12

General Boards => General National 12 chat => Topic started by: DuncanAdams on June 27, 2019, 08:07:39 AM

Title: Off the boom sheeting
Post by: DuncanAdams on June 27, 2019, 08:07:39 AM
I'm thinking of converting the my 12 to an off the boom sheeting system.

Does anyone know of there is an off the shelf way of doing it?
Or is the a really bad idea?!  :o
Title: Re: Off the boom sheeting
Post by: John M on June 27, 2019, 07:16:40 PM
Most people at the front of the fleet use rear sheeting, but there are notable exceptions to this too.  It is therefore not a bad idea.

They tend to have a split end mainsheet tied to the transom and then to a block on the outboard end of the boom and to a ratchet block on the boom.  Be carefully not to get garrotted by a loop that then dangles from the boom when you tack.

I think the benefits are generally downwind.  Upwind you must keep the boom centrelines and you have to use more kicker adjustment to get the leech of the sail to be perfect.  This is achievable but harder.

John
Title: Re: Off the boom sheeting
Post by: johnk on June 27, 2019, 09:05:01 PM
Toppers et al use a tube of fabric to surround the (loose footed) boom and mainsheet between the rear of the boom and the take off point. This reduces the risk of garrotting!
Title: Re: Off the boom sheeting
Post by: DuncanAdams on June 28, 2019, 08:11:02 AM
Thanks, chaps, have gotten my sewing machine out for V1 stop!
Many thanks
Title: Re: Off the boom sheeting
Post by: JayHaich on July 01, 2019, 02:27:50 PM
I'm one of the few using off-the-boom sheeting, my boat came with this fitted and I have stuck with it.  See photos of 3519 on the boat database.  To me the main positive is you face forward when gybing.  Getting the boom on the centreline upwind is easy because the sheet from centre ratchet block to helms hand gives a strong horizontal component pulling boom to windward.  Because of this you can make the aft split tail a bit shorter than is common for aft main boats.  This allows you to pull down on the leech with the last bit of mainsheet.  Downwind sheet loads get heavy in strong wind, placing the ratchet block on the boom a little aft of the middle helps reduce the load.   
Title: Re: Off the boom sheeting
Post by: DuncanAdams on July 01, 2019, 08:15:22 PM
Thanks. I set it up this weekend and felt so much better.
Sadly the blocks have now pulled out of the floor for the kicker.

Fun and games  ;)